Refurbished Mixshield sets a fast pace in The Hague 30 May 2019

A refurbished 11.34m diameter Mixshield TBM from Herreknecht has taken just one year to successfully excavate the twin tubes of the 1.6km Victory Boogie Woogie road tunnel as part of of the 4km Rotterdamsebaan project to connect the Ypenburg interchange with the ring road of The Hague in the Netherlands.

Open spoke cutting wheel with central material transport

To overcome challenging ground conditions due to more than half of the country being below sea level, project partners were able to draw on previous experiences. Between 2013 and 2015, the same Herrenknecht Mixshield excavated the Sluiskil Tunnel in the Netherlands.

After refurbishment at the Herrenknecht plant in Kehl, the TBM started work on the first of the two 1.6km long, 10.15m i.d. tunnels for the Rotterdamsebaan road link in January 2018 and broke through in July 2018. After disassembly, return transport to the working portal, and reassembly, the TBM and its site crew then quickly excavated the second tube between September 2018 and January 2019.

At more than 1,600 tonnes and about 80m long, the reused TBM achieved advance rates of up to 16.9m/day for the Combinatie Rotterdamsebaan JV comprising Wayss & Freytag, BAM Infra and VolkerWessels. The JV is responsible for the design, preparation and realisation of the project, and will also maintain the total 4km-long link road for a period of 15 years.

The TBM, originally designed to excavate the heterogeneous sand, silt and clogging-prone clay geological conditions of the Sluiskil Tunnel, has an open spoke cutting wheel with direct material transport from the cutting wheel centre and an optimally adapted slurry circuit.

In a reference to Victory Boogie Woogie work of art by Dutch painter Piet Mondrian, from which the tunnel takes its name, the cutting wheel was painted in yellow, red and blue. Due to the low abrasiveness of the soil, the colours were still clearly visible after final breakthrough.

Final breakthrough in January 2019

Herrenknecht Mixshield TBMs are designed to support an unstable tunnel face. A liquid medium or suspension is used, which is kept under a controlled pressure. When support pressure of the slurry medium in the excavation chamber corresponds to the surrounding earth and groundwater pressure, the tunnel face is stabilised, avoiding uncontrolled inflow of soil and minimal settlement or heave on the surface. This was necessary on the the new tunnel alignment that runs beneath the busy inner-city areas of The Hague.

After commissioning in July 2020, the new road link will improve traffic for commuters and significantly reduce congestion on the Utrechtsebaan and other traffic routes in the area.